/* ===== 耳思编程 - Premium Dark Tech UI ===== */
/* 字体通过 HTML preconnect + preload 加载，见 base.html / login.html */

.display { font-family: 'ZCOOL QingKe HuangYou', 'PingFang SC', sans-serif; }

/* Page view transitions */
#worksView, #materialsView, #classesView, #hoursView {
  animation: fadeIn 0.25s var(--ease);
}

/* ZCOOL 仅用于大标题（字间距加大提升可读性） */
h1, .page-header h1,
body.student-view .page-header h1 {
  font-family: 'ZCOOL QingKe HuangYou', 'PingFang SC', sans-serif;
  letter-spacing: 0.08em;
}

/* 中小标题用 Inter 保持清晰 */
h2, h3,
.stat-value,
.modal-title,
.student-view .work-title,
.toast {
  font-family: 'Inter', -apple-system, 'PingFang SC', sans-serif;
  letter-spacing: -0.02em;
}

:root {
  --bg-0: #060a13;
  --bg-1: #0b1120;
  --bg-2: #111a2e;
  --bg-3: #172036;
  --bg-4: #1e2a45;
  --bg-5: #253354;

  --border-1: rgba(255,255,255,0.06);
  --border-2: rgba(255,255,255,0.10);
  --border-3: rgba(255,255,255,0.16);

  --text-1: #f0f2f5;
  --text-2: #c0c7d4;
  --text-3: #8892a6;
  --text-4: #555f73;

  --accent: #7c5cfc;
  --accent-light: #a78bfa;
  --accent-dark: #5b3fd6;
  --accent-glow: rgba(124,92,252,0.25);
  --accent-glow-lg: rgba(124,92,252,0.40);

  --cyan: #22d3ee;

  --green: #34d399;
  --green-bg: rgba(52,211,153,0.12);
  --red: #f87171;
  --red-bg: rgba(248,113,113,0.12);
  --amber: #fbbf24;
  --amber-bg: rgba(251,191,36,0.12);

  --scratch: #ff8c1a;
  --scratch-bg: rgba(255,140,26,0.12);
  --python: #3b82f6;
  --python-bg: rgba(59,130,246,0.12);
  --cpp: #ee172c;
  --cpp-bg: rgba(238,23,44,0.12);

  --glass: rgba(15,23,42,0.65);
  --glass-border: rgba(255,255,255,0.08);
  --glass-hover: rgba(255,255,255,0.04);

  --radius: 14px;
  --radius-sm: 10px;
  --radius-xs: 6px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --shadow: 0 1px 3px rgba(0,0,0,0.4), 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.5), 0 12px 40px rgba(0,0,0,0.4);

  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.33, 1, 0.68, 1);
  --duration: 0.25s;
}

/* ===== Light Theme ===== */
[data-theme="light"] {
  --bg-0: #f0f2f5;
  --bg-1: #f7f8fa;
  --bg-2: #ffffff;
  --bg-3: #eef0f4;
  --bg-4: #e4e7ed;
  --bg-5: #d9dde5;

  --border-1: rgba(0,0,0,0.06);
  --border-2: rgba(0,0,0,0.10);
  --border-3: rgba(0,0,0,0.16);

  --text-1: #1a1d26;
  --text-2: #4a5068;
  --text-3: #6b7280;
  --text-4: #9ca3af;

  --glass: rgba(255,255,255,0.82);
  --glass-border: rgba(0,0,0,0.06);
  --glass-hover: rgba(0,0,0,0.03);

  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.04);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.08), 0 12px 40px rgba(0,0,0,0.06);
}

[data-theme="light"] .bg-grid {
  background-image:
    linear-gradient(rgba(124,92,252,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(124,92,252,0.04) 1px, transparent 1px);
}
[data-theme="light"] .bg-grid::before {
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(124,92,252,0.06), transparent),
              radial-gradient(ellipse 60% 50% at 80% 100%, rgba(34,211,238,0.03), transparent);
}

[data-theme="light"] .page-header {
  background: rgba(247,248,250,0.85);
}

[data-theme="light"] .nav-link.active {
  color: var(--accent-dark);
}

[data-theme="light"] .work-card:hover {
  box-shadow: 0 8px 32px rgba(0,0,0,0.10), 0 0 0 1px var(--accent-glow);
}

[data-theme="light"] .work-thumb::after {
  background: linear-gradient(180deg, transparent 60%, var(--bg-2));
}

[data-theme="light"] .sidebar-overlay {
  background: rgba(0,0,0,0.2);
}

[data-theme="light"] .modal-overlay {
  background: rgba(0,0,0,0.3);
}

[data-theme="light"] .leave-modal {
  background: rgba(255,255,255,0.9);
  box-shadow: 0 20px 60px rgba(0,0,0,0.15);
}

[data-theme="light"] .toast {
  backdrop-filter: blur(12px);
}

[data-theme="light"] ::selection {
  background: var(--accent);
  color: #fff;
}

[data-theme="light"] .mobile-header {
  background: rgba(255,255,255,0.85);
}

[data-theme="light"] .form-select option {
  background: var(--bg-2);
}

/* Light mode: 表单/表格/空状态补充 */
[data-theme="light"] .card,
[data-theme="light"] .stat-card {
  background: var(--bg-2);
  border-color: var(--border-2);
}
[data-theme="light"] .form-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%236b7280' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
}
[data-theme="light"] .stat-card:hover {
  border-color: var(--border-3);
}
[data-theme="light"] .data-table th {
  background: var(--bg-3);
  border-bottom-color: var(--border-2);
}
[data-theme="light"] .data-table td {
  border-bottom-color: var(--border-1);
  background: var(--bg-2);
}
[data-theme="light"] .data-table tbody tr:hover td {
  background: var(--bg-3);
}
[data-theme="light"] .user-card {
  border-color: var(--border-1);
}
[data-theme="light"] .tabs-bar {
  background: var(--bg-3);
  border-color: var(--border-2);
}
[data-theme="light"] .tab-btn.active {
  background: var(--bg-2);
  border-color: var(--border-2);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
  color: var(--accent-dark);
}
[data-theme="light"] .empty-state {
  background: transparent;
}
[data-theme="light"] .badge-default {
  background: rgba(99,102,241,0.08);
  color: #4f46e5;
}
[data-theme="light"] .search-input {
  background: var(--bg-2);
}
[data-theme="light"] .theme-toggle-btn::after {
  background: var(--bg-4);
}
[data-theme="light"] .student-works-empty {
  background: transparent;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg-0);
  color: var(--text-1);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== Skip-to-content（无障碍跳转） ===== */
.skip-link {
  position: fixed; top: -100%; left: 50%; transform: translateX(-50%);
  z-index: 9999; padding: 10px 24px;
  background: var(--accent); color: #fff;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-size: 14px; font-weight: 600; text-decoration: none;
  transition: top 0.25s var(--ease);
  font-family: inherit;
}
.skip-link:focus { top: 0; }

/* ===== Student View ===== */
body.student-view {
  --student-radius: 18px;
  font-size: 15.5px;
}
body.student-view .btn {
  border-radius: 12px;
  font-weight: 700;
  padding: 10px 20px;
}
body.student-view .work-card {
  border-radius: var(--student-radius);
  border-width: 1.5px;
}
body.student-view .work-card .work-title {
  font-size: 16px;
}
body.student-view .page-header h1 {
  font-size: 26px;
}
body.student-view .form-input,
body.student-view .form-select,
body.student-view .form-textarea {
  border-radius: 10px;
  padding: 12px 16px;
  font-size: 14px;
}
body.student-view .badge {
  font-size: 12.5px;
  padding: 4px 12px;
  border-radius: 22px;
}
body.student-view .stat-value {
  font-size: 32px;
}
body.student-view .toast {
  border-radius: 16px;
  padding: 14px 22px;
}

/* ===== Teacher View ===== */
body.teacher-view .page-header h1 {
  font-family: 'Inter', sans-serif;
  font-weight: 800;
  letter-spacing: -0.5px;
}

a { color: var(--accent-light); text-decoration: none; transition: color var(--duration) var(--ease); }
a:hover { color: var(--accent); }

::selection { background: var(--accent); color: #fff; }

/* Scrollbar */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-2); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-3); }

/* ===== ANIMATED BACKGROUND ===== */
.bg-grid {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(rgba(124,92,252,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(124,92,252,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
}
.bg-grid::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(124,92,252,0.08), transparent),
              radial-gradient(ellipse 60% 50% at 80% 100%, rgba(34,211,238,0.04), transparent);
}

/* ===== LAYOUT ===== */
.app-container { display: flex; min-height: 100vh; }

/* Sidebar */
.sidebar {
  width: 260px;
  background: var(--glass);
  backdrop-filter: blur(20px) saturate(1.5);
  -webkit-backdrop-filter: blur(20px) saturate(1.5);
  border-right: 1px solid var(--glass-border);
  display: flex; flex-direction: column;
  position: fixed; top: 0; left: 0; bottom: 0;
  z-index: 100;
  transition: transform var(--duration) var(--ease);
}

.sidebar-logo {
  padding: 24px;
  border-bottom: 1px solid var(--border-1);
  display: flex; align-items: center; gap: 14px;
}

/* Sidebar check-in button */
.sidebar-checkin {
  margin-left: auto;
  height: 32px; padding: 0 12px;
  border-radius: 8px;
  display: inline-flex; align-items: center; gap: 4px;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  box-shadow: 0 2px 8px var(--accent-glow);
  transition: all var(--duration) var(--ease);
  flex-shrink: 0;
  font-size: 12px; font-weight: 700; color: #fff;
  font-family: inherit; border: none;
  white-space: nowrap;
}
.sidebar-checkin:hover {
  box-shadow: 0 4px 16px var(--accent-glow-lg);
  transform: scale(1.05);
}
.sidebar-checkin:active { transform: scale(0.95); }
.sidebar-checkin.checked-in {
  background: linear-gradient(135deg, #059669, #047857);
  box-shadow: 0 2px 10px rgba(5,150,105,0.3);
}
.sidebar-checkin.checked-in:hover {
  box-shadow: 0 4px 16px rgba(5,150,105,0.4);
}

.logo-mark {
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  flex-shrink: 0;
}
.logo-mark img {
  width: 100%; height: 100%; object-fit: cover;
  display: block;
}

.logo-text {
  font-size: 17px; font-weight: 700; letter-spacing: -0.3px;
}
.logo-sub {
  font-size: 11px; color: var(--text-4); font-weight: 400; margin-top: 1px;
}

.sidebar-nav { flex: 1; padding: 20px 14px; overflow-y: auto; }

.nav-group { margin-bottom: 8px; }
.nav-group-title {
  font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--text-4);
  padding: 12px 12px 8px;
}

.nav-link {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: var(--radius-xs);
  color: var(--text-3); cursor: pointer;
  transition: all var(--duration) var(--ease);
  font-size: 13.5px; font-weight: 500;
  position: relative; overflow: hidden;
  border: 1px solid transparent;
}
/* Active indicator line */
.nav-link::before {
  content: '';
  position: absolute; left: 0; top: 50%; transform: translateY(-50%);
  width: 3px; height: 0;
  border-radius: 0 3px 3px 0;
  background: var(--accent);
  transition: height 0.3s var(--ease);
}
.nav-link:hover::before {
  height: 16px;
}
.nav-link.active::before {
  height: 24px;
}
.nav-link:hover {
  color: var(--text-1);
  background: var(--glass-hover);
}
.nav-link.active {
  color: #fff;
  background: linear-gradient(135deg, rgba(124,92,252,0.18), rgba(124,92,252,0.08));
  border-color: rgba(124,92,252,0.25);
  box-shadow: inset 0 0 20px rgba(124,92,252,0.05);
}
.nav-link .nav-icon {
  width: 20px; height: 20px; display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.nav-link .nav-icon svg { width: 18px; height: 18px; opacity: 0.7; }
.nav-link.active .nav-icon svg { opacity: 1; }
.nav-logout svg { width: 18px; height: 18px; opacity: 0.6; flex-shrink: 0; }

/* Global SVG constraint */
.nav-icon svg {
  width: 18px !important;
  height: 18px !important;
  flex-shrink: 0;
}

.nav-link .nav-badge {
  margin-left: auto;
  font-size: 11px; padding: 1px 7px;
  background: var(--accent-glow);
  color: var(--accent-light);
  border-radius: 10px; font-weight: 600;
}

/* Sidebar footer */
.sidebar-footer {
  padding: 14px;
  border-top: 1px solid var(--border-1);
}

.user-card {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 12px; border-radius: var(--radius-sm);
  background: var(--border-1);
  border: 1px solid var(--border-2);
}
.user-card .theme-toggle-btn {
  margin-left: auto;
}
.user-avatar {
  width: 34px; height: 34px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #a78bfa);
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; color: #fff; font-weight: 700;
  flex-shrink: 0;
  box-shadow: 0 2px 8px var(--accent-glow);
}
.user-info { flex: 1; min-width: 0; }
.user-info-name { font-size: 13px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.user-info-role { font-size: 11px; color: var(--text-4); font-weight: 500; }

.nav-logout {
  margin-top: 8px;
  display: flex; align-items: center; gap: 10px;
  padding: 9px 12px; border-radius: var(--radius-xs);
  color: var(--text-4); cursor: pointer;
  transition: all var(--duration) var(--ease);
  font-size: 13px; font-weight: 500;
}
.nav-logout:hover { color: var(--red); background: var(--red-bg); }
.nav-logout svg { width: 18px; height: 18px; opacity: 0.6; }

/* Theme toggle */
.theme-toggle-btn {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: var(--radius-xs);
  background: var(--border-1); border: 1px solid var(--border-2);
  cursor: pointer; color: var(--text-3);
  transition: all var(--duration) var(--ease);
  flex-shrink: 0;
}
.theme-toggle-btn:hover {
  color: var(--accent); background: var(--accent-glow);
  border-color: rgba(124,92,252,0.25);
}
.theme-toggle-btn svg { width: 18px; height: 18px; }

/* Main content */
.main-content {
  flex: 1; margin-left: 260px;
  min-height: 100vh;
}

.page-header {
  padding: 20px 32px;
  border-bottom: 1px solid var(--border-1);
  background: rgba(6,10,19,0.7);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  display: flex; justify-content: space-between; align-items: center;
  position: sticky; top: 0; z-index: 50;
}
/* Page header action buttons: 统一高度 */
.page-header > div:last-child .btn,
.page-header > .btn {
  padding: 8px 16px;
  font-size: 13px;
}
.page-header h1 { font-size: 20px; font-weight: 700; letter-spacing: -0.3px; }
.page-header .subtitle { font-size: 13px; color: var(--text-4); margin-top: 2px; }

.page-body { padding: 28px 32px; }

/* ===== COMPONENTS ===== */

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 9px 18px; border-radius: var(--radius-sm);
  font-size: 13px; font-weight: 600; cursor: pointer;
  border: none; outline: none;
  transition: all var(--duration) var(--ease);
  position: relative; overflow: hidden;
  white-space: nowrap;
  font-family: inherit;
  -webkit-tap-highlight-color: transparent;
  text-decoration: none;
  line-height: 1.4;
}
/* Ripple effect on click */
.btn::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(circle at var(--click-x, 50%) var(--click-y, 50%), 
              rgba(255,255,255,0.2) 0%, transparent 60%);
  opacity: 0;
  transition: opacity 0.4s var(--ease-out);
  pointer-events: none;
}
.btn:active::after {
  opacity: 1;
  transition: opacity 0s;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  color: #fff;
  box-shadow: 0 2px 12px var(--accent-glow);
}
.btn-primary:hover {
  box-shadow: 0 4px 24px var(--accent-glow-lg);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-2);
  border: 1px solid var(--border-2);
}
.btn-ghost:hover {
  background: var(--border-1);
  border-color: var(--border-3);
  color: var(--text-1);
}

.btn-success {
  background: linear-gradient(135deg, var(--green), #059669);
  color: #fff;
  box-shadow: 0 2px 12px rgba(52,211,153,0.25);
}
.btn-success:hover { box-shadow: 0 4px 20px rgba(52,211,153,0.35); transform: translateY(-1px); }

.btn-danger {
  background: linear-gradient(135deg, var(--red), #dc2626);
  color: #fff;
}
.btn-danger:hover { box-shadow: 0 4px 16px rgba(248,113,113,0.3); transform: translateY(-1px); }

/* Outline button variant */
.btn-outline {
  background: transparent;
  color: var(--text-2);
  border: 1px solid var(--border-2);
}
.btn-outline:hover { background: var(--bg-2); border-color: var(--accent); color: var(--accent-light); }

.btn-sm { padding: 6px 12px; font-size: 12px; border-radius: var(--radius-xs); }
.btn-lg { padding: 12px 28px; font-size: 15px; border-radius: var(--radius-sm); }
.btn-create { padding: 11px 22px; font-size: 14px; border-radius: var(--radius-sm); font-weight: 700; }
.btn-icon { padding: 8px; min-width: 34px; }

.btn-scratch {
  background: linear-gradient(135deg, var(--scratch), #e06b00);
  color: #fff;
  box-shadow: 0 2px 12px rgba(255,140,26,0.25);
}
.btn-scratch:hover { box-shadow: 0 4px 20px rgba(255,140,26,0.35); transform: translateY(-1px); }

.btn-python {
  background: linear-gradient(135deg, var(--python), #2563eb);
  color: #fff;
  box-shadow: 0 2px 12px rgba(59,130,246,0.25);
}
.btn-python:hover { box-shadow: 0 4px 20px rgba(59,130,246,0.35); transform: translateY(-1px); }

.btn-cpp {
  background: linear-gradient(135deg, var(--cpp), #b91c1c);
  color: #fff;
  box-shadow: 0 2px 12px rgba(238,23,44,0.25);
}
.btn-cpp:hover { box-shadow: 0 4px 20px rgba(238,23,44,0.35); transform: translateY(-1px); }

/* Cards */
.card {
  background: var(--glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--duration) var(--ease);
}
.card:hover {
  border-color: var(--border-2);
}

/* Stat Cards */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; }

.stat-card {
  background: var(--glass);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 22px 24px;
  display: flex; align-items: center; gap: 16px;
  transition: all var(--duration) var(--ease);
  position: relative; overflow: hidden;
}
.stat-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  border-radius: var(--radius) var(--radius) 0 0;
}
.stat-card.purple::before { background: linear-gradient(90deg, var(--accent), #a78bfa); }
.stat-card.green::before { background: linear-gradient(90deg, var(--green), var(--cyan)); }
.stat-card.blue::before { background: linear-gradient(90deg, var(--python), #60a5fa); }
.stat-card.amber::before { background: linear-gradient(90deg, var(--amber), #f97316); }

.stat-card:hover { border-color: var(--border-2); transform: translateY(-2px); box-shadow: var(--shadow); }

.stat-icon {
  width: 48px; height: 48px; border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; flex-shrink: 0;
}
.stat-icon.purple { background: rgba(124,92,252,0.12); }
.stat-icon.green { background: var(--green-bg); }
.stat-icon.blue { background: var(--python-bg); }
.stat-icon.amber { background: var(--amber-bg); }
.stat-icon.cyan { background: rgba(34,211,238,0.12); }

.stat-value { font-size: 28px; font-weight: 800; letter-spacing: -1px; line-height: 1.1; }
.stat-label { font-size: 13px; color: var(--text-4); font-weight: 500; margin-top: 2px; }

/* Grid */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-5 { grid-template-columns: repeat(5, 1fr); }

/* Table */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--border-1); }
.data-table { width: 100%; border-collapse: collapse; }
.data-table th {
  padding: 14px 18px; text-align: left;
  font-size: 11px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1px; color: var(--text-4);
  background: var(--bg-1);
  border-bottom: 1px solid var(--border-1);
}
.data-table td {
  padding: 14px 18px;
  font-size: 13.5px; color: var(--text-2);
  border-bottom: 1px solid var(--border-1);
}
.data-table tbody tr {
  transition: background var(--duration) var(--ease);
}
.data-table tbody tr:hover { background: var(--bg-3); }
.data-table tbody tr:hover td:first-child {
  box-shadow: inset 3px 0 0 var(--accent);
}
.data-table tbody tr:last-child td { border-bottom: none; }

/* Badge */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 10px; border-radius: 20px;
  font-size: 11.5px; font-weight: 600;
  letter-spacing: 0.2px;
}
.badge-scratch { background: var(--scratch-bg); color: var(--scratch); }
.badge-python { background: var(--python-bg); color: var(--python); }
.badge-cpp { background: var(--cpp-bg); color: var(--cpp); }
.badge-default { background: rgba(99,102,241,0.12); color: #6366f1; }
.badge-success { background: var(--green-bg); color: var(--green); }
.badge-warning { background: var(--amber-bg); color: var(--amber); }
.badge-danger { background: var(--red-bg); color: var(--red); }
.badge-accent { background: rgba(124,92,252,0.12); color: var(--accent-light); }

/* Tag */
.tag {
  display: inline-flex; padding: 3px 10px; border-radius: 6px;
  font-size: 12px; font-weight: 500;
  background: var(--bg-3); color: var(--text-2);
  border: 1px solid var(--border-1);
}

/* Modal */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.65);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  opacity: 0; visibility: hidden;
  transition: all 0.3s var(--ease);
}
.modal-overlay.active { opacity: 1; visibility: visible; }
.modal {
  background: var(--bg-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius-lg);
  padding: 28px;
  width: 90%; max-width: 500px;
  max-height: 85vh; overflow-y: auto;
  box-shadow: var(--shadow-lg);
  transform: translateY(24px) scale(0.96);
  transition: all 0.35s var(--ease);
}
.modal-overlay.active .modal { transform: translateY(0) scale(1); }
.modal-title {
  font-size: 18px; font-weight: 700; margin-bottom: 24px;
  padding-bottom: 16px; border-bottom: 1px solid var(--border-1);
  letter-spacing: -0.3px;
}
.modal-footer {
  display: flex; justify-content: flex-end; gap: 10px;
  margin-top: 24px; padding-top: 16px;
  border-top: 1px solid var(--border-1);
}

/* Form */
.form-group { margin-bottom: 18px; }
.form-label {
  display: block; font-size: 12.5px; font-weight: 600;
  color: var(--text-3); margin-bottom: 7px;
  letter-spacing: 0.2px;
}
.form-input, .form-select, .form-textarea {
  width: 100%; padding: 10px 14px;
  background: var(--bg-1);
  border: 1px solid var(--border-2);
  border-radius: var(--radius-xs);
  color: var(--text-1); font-size: 13.5px;
  transition: all var(--duration) var(--ease);
  outline: none; font-family: inherit;
}
.form-input::placeholder { color: var(--text-4); }
.form-input:focus, .form-select:focus, .form-textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow), 0 0 20px var(--accent-glow);
  background: var(--bg-2);
  transform: scale(1.01);
}
.form-textarea { min-height: 80px; resize: vertical; line-height: 1.5; }
.form-select { cursor: pointer; appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%238892a6' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 12px center; padding-right: 32px; }
.form-select option { background: var(--bg-2); color: var(--text-1); }

/* Toast */
.toast-container { position: fixed; top: 20px; right: 20px; z-index: 2000; display: flex; flex-direction: column; gap: 8px; }
.toast {
  padding: 12px 20px; border-radius: var(--radius-sm);
  font-size: 13.5px; font-weight: 500;
  box-shadow: var(--shadow-lg);
  animation: toastIn 0.4s var(--ease);
  display: flex; align-items: center; gap: 8px;
  border: 1px solid var(--border-1);
  backdrop-filter: blur(12px);
}
.toast-success { background: rgba(5,150,105,0.9); color: #fff; border-color: rgba(52,211,153,0.3); }
.toast-error { background: rgba(185,28,28,0.9); color: #fff; border-color: rgba(248,113,113,0.3); }
.toast-info { background: rgba(91,63,214,0.9); color: #fff; border-color: rgba(124,92,252,0.3); }

@keyframes toastIn {
  from { transform: translateX(120%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* Tabs */
.tabs-bar {
  display: inline-flex; gap: 2px; padding: 4px;
  background: var(--bg-1); border-radius: var(--radius-sm);
  border: 1px solid var(--border-1);
}
.tab-btn {
  padding: 7px 18px; border-radius: var(--radius-xs);
  font-size: 13px; font-weight: 500;
  color: var(--text-3); cursor: pointer;
  transition: all var(--duration) var(--ease);
  border: 1px solid transparent; background: none;
  font-family: inherit;
}
.tab-btn:hover { color: var(--text-1); }
.tab-btn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 8px var(--accent-glow);
}

/* Search */
.search-input {
  display: flex; align-items: center; gap: 8px;
  background: var(--bg-1); border: 1px solid var(--border-2);
  border-radius: var(--radius-xs); padding: 0 14px;
  transition: all var(--duration) var(--ease);
}
.search-input:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.search-input svg { width: 16px; height: 16px; color: var(--text-4); flex-shrink: 0; }
.search-input input {
  flex: 1; padding: 9px 0; background: transparent;
  border: none; color: var(--text-1); font-size: 13px;
  outline: none; font-family: inherit;
}
.search-input input::placeholder { color: var(--text-4); }

/* Work Cards */
.work-card {
  background: var(--bg-2);
  border: 1px solid var(--border-1);
  border-radius: var(--radius);
  overflow: hidden; cursor: pointer;
  transition: border-color var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
  position: relative;
  isolation: isolate;
}

/* 聚光灯扫过效果（替代 translateY） */
.work-card::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(320px circle at 50% -10%, 
              var(--accent-glow), transparent 60%);
  opacity: 0;
  transition: opacity 0.6s var(--ease-out);
  pointer-events: none; z-index: 1;
}
.work-card:hover::before {
  opacity: 1;
}
.work-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-glow), 0 12px 40px rgba(0,0,0,0.5);
}
.work-thumb {
  width: 100%; aspect-ratio: 4/3;
  background: var(--bg-1);
  display: flex; align-items: center; justify-content: center;
  overflow: hidden; position: relative;
}
.work-thumb img { width: 100%; height: 100%; object-fit: cover; 
  transition: transform 0.6s var(--ease-out); }
.work-card:hover .work-thumb img { transform: scale(1.08); }
.work-thumb .placeholder { font-size: 36px; opacity: 0.25; }
.work-thumb::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, var(--bg-2));
  opacity: 0; transition: opacity var(--duration) var(--ease);
}
.work-card:hover .work-thumb::after { opacity: 1; }

.work-info { padding: 10px 12px 4px; position: relative; z-index: 2; }
.work-title {
  font-size: 12.5px; font-weight: 600;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  letter-spacing: -0.2px;
  transition: color 0.3s var(--ease);
}
.work-card:hover .work-title { color: var(--accent-light); }
.work-meta {
  font-size: 11px; color: var(--text-4); margin-top: 4px;
  display: flex; justify-content: space-between; align-items: center;
}
.work-actions {
  padding: 6px 12px 10px;
  display: flex; gap: 5px;
  opacity: 0; transform: translateY(4px);
  transition: all var(--duration) var(--ease);
  position: relative; z-index: 2;
}
.work-card:hover .work-actions { opacity: 1; transform: translateY(0); }

/* Empty State */
.empty-state {
  text-align: center; padding: 80px 24px;
  color: var(--text-4);
}
.empty-state .empty-icon { font-size: 56px; margin-bottom: 20px; opacity: 0.2; }
.empty-state .empty-title { font-size: 17px; font-weight: 600; color: var(--text-3); margin-bottom: 8px; }
.empty-state .empty-desc { font-size: 13.5px; max-width: 300px; margin: 0 auto; line-height: 1.7; }
.empty-state .btn { margin-top: 24px; }

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes slideInRight {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}
@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.5; } }
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.animate-fade-in { animation: fadeIn 0.5s var(--ease) both; }
.animate-fade-in-up { animation: fadeInUp 0.5s var(--ease) both; }
.animate-scale-in { animation: scaleIn 0.4s var(--ease) both; }

/* Stagger animation for grid items */
.work-card { animation: fadeInUp 0.4s var(--ease) both; }
.work-card:nth-child(1) { animation-delay: 0ms; }
.work-card:nth-child(2) { animation-delay: 40ms; }
.work-card:nth-child(3) { animation-delay: 80ms; }
.work-card:nth-child(4) { animation-delay: 120ms; }
.work-card:nth-child(5) { animation-delay: 160ms; }
.work-card:nth-child(6) { animation-delay: 200ms; }
.work-card:nth-child(7) { animation-delay: 240ms; }
.work-card:nth-child(8) { animation-delay: 280ms; }

/* Mobile header */
.mobile-header {
  display: none;
  position: sticky; top: 0; z-index: 90;
  height: 56px;
  background: var(--glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--glass-border);
  padding: 0 16px;
  align-items: center; justify-content: space-between;
}
.mobile-header-left { display: flex; align-items: center; gap: 12px; }
.mobile-header-title {
  font-size: 16px; font-weight: 700; letter-spacing: -0.2px;
}
.mobile-header-right { display: flex; align-items: center; gap: 8px; }

/* Hamburger button */
.hamburger {
  display: none;
  width: 36px; height: 36px;
  align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  border-radius: var(--radius-xs);
  transition: all var(--duration) var(--ease);
  color: var(--text-2);
}
.hamburger:hover { background: var(--border-1); color: var(--text-1); }
.hamburger svg { width: 22px; height: 22px; }

/* Sidebar overlay for mobile */
.sidebar-overlay {
  display: none;
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 99;
  opacity: 0; visibility: hidden;
  transition: all 0.3s var(--ease);
}
.sidebar-overlay.active { opacity: 1; visibility: visible; }

/* Confirm dialog */
.confirm-dialog {
  text-align: center; padding: 8px 0;
}
.confirm-dialog .confirm-icon {
  width: 56px; height: 56px;
  border-radius: 50%;
  background: var(--amber-bg);
  display: inline-flex; align-items: center; justify-content: center;
  margin-bottom: 16px;
}
.confirm-dialog .confirm-icon.danger { background: var(--red-bg); }
.confirm-dialog .confirm-icon svg { width: 28px; height: 28px; color: var(--amber); }
.confirm-dialog .confirm-icon.danger svg { color: var(--red); }
.confirm-dialog .confirm-title {
  font-size: 17px; font-weight: 700; margin-bottom: 8px;
  color: var(--text-1);
}
.confirm-dialog .confirm-message {
  font-size: 14px; color: var(--text-3); line-height: 1.6;
  margin-bottom: 24px;
}
.confirm-dialog .confirm-actions {
  display: flex; gap: 10px; justify-content: center;
}

/* Prompt dialog */
.prompt-dialog { padding: 8px 0; }
.prompt-dialog .prompt-title {
  font-size: 17px; font-weight: 700; margin-bottom: 16px;
  color: var(--text-1);
}
.prompt-dialog .prompt-input {
  width: 100%; padding: 10px 14px;
  background: var(--bg-1); border: 1px solid var(--border-2);
  border-radius: var(--radius-xs);
  color: var(--text-1); font-size: 14px;
  outline: none; font-family: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
  box-sizing: border-box;
}
.prompt-dialog .prompt-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.prompt-dialog .prompt-actions {
  display: flex; gap: 10px; justify-content: flex-end;
  margin-top: 20px;
}

/* Skeleton loading */
.skeleton {
  background: linear-gradient(90deg, var(--bg-2) 25%, var(--bg-3) 50%, var(--bg-2) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-xs);
}
.skeleton-card {
  background: var(--bg-2);
  border: 1px solid var(--border-1);
  border-radius: var(--radius);
  overflow: hidden;
}
.skeleton-thumb {
  width: 100%; aspect-ratio: 4/3;
  background: linear-gradient(90deg, var(--bg-1) 25%, var(--bg-2) 50%, var(--bg-1) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}
.skeleton-text { height: 14px; margin: 12px 16px 0; border-radius: 4px; }
.skeleton-text.short { width: 60%; }
.skeleton-badge { height: 10px; width: 60px; margin: 8px 16px 16px; border-radius: 12px; }
.skeleton-row {
  display: flex; gap: 16px; padding: 14px 18px;
  border-bottom: 1px solid var(--border-1);
}
.skeleton-cell { height: 14px; border-radius: 4px; }
.skeleton-cell.w-full { flex: 1; }
.skeleton-cell.w-half { flex: 0.5; }
.skeleton-cell.w-third { flex: 0.33; }
.skeleton-cell.w-20 { width: 80px; }

/* Responsive */
@media (max-width: 1200px) {
  .grid-4 { grid-template-columns: repeat(3, 1fr); }
  .grid-5 { grid-template-columns: repeat(3, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

/* 1024-1200px 中间态 */
@media (max-width: 1100px) {
  .grid-5 { grid-template-columns: repeat(3, 1fr); }
  .sidebar { width: 220px; }
  .main-content { margin-left: 220px; }
}

@media (max-width: 1024px) {
  .sidebar { width: 240px; }
  .main-content { margin-left: 240px; }
}

@media (max-width: 768px) {
  /* Show mobile elements */
  .hamburger { display: flex; }
  .mobile-header { display: flex; }
  .sidebar-overlay { display: block; }

  /* Sidebar as drawer */
  .sidebar {
    transform: translateX(-100%);
    width: 280px;
    box-shadow: var(--shadow-lg);
  }
  .sidebar.open { transform: translateX(0); }

  /* Main content fills screen */
  .main-content { margin-left: 0; }

  /* Grids */
  .grid-2 { grid-template-columns: 1fr; }
  .grid-3, .grid-4, .grid-5 { grid-template-columns: repeat(2, 1fr); }

  /* Page layout */
  .page-body { padding: 16px; }
  .page-header {
    padding: 14px 16px;
    flex-wrap: wrap; gap: 12px;
    border-bottom: none;
    position: static;
  }
  .page-header h1 { font-size: 18px; }
  .page-header .subtitle { display: none; }
  .page-header > div:last-child {
    width: 100%;
    display: flex; gap: 8px;
    overflow-x: auto; -webkit-overflow-scrolling: touch;
    padding-bottom: 4px;
    scrollbar-width: none;
  }
  .page-header > div:last-child::-webkit-scrollbar { display: none; }

  /* Stats grid */
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
  .stat-card { padding: 16px; gap: 12px; }
  .stat-value { font-size: 22px; }
  .stat-icon { width: 40px; height: 40px; }

  /* Work cards - actions always visible on touch */
  .work-actions {
    opacity: 1; transform: translateY(0);
  }
  .work-card:hover {
    box-shadow: none;
  }
  .work-card:hover .work-thumb::after { opacity: 0; }

  /* Table responsive - card mode */
  .table-wrap { border: none; }
  .data-table thead { display: none; }
  .data-table tbody tr {
    display: block;
    background: var(--bg-2);
    border: 1px solid var(--border-1);
    border-radius: var(--radius-sm);
    margin-bottom: 10px;
    padding: 12px 16px;
  }
  .data-table tbody tr:hover { background: var(--bg-3); }
  .data-table td {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 0;
    border-bottom: 1px solid var(--border-1);
    font-size: 13px;
  }
  .data-table td:last-child { border-bottom: none; justify-content: flex-start; }
  .data-table td::before {
    content: attr(data-label);
    font-size: 11px; font-weight: 600;
    color: var(--text-4);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    flex-shrink: 0;
    margin-right: 12px;
  }

  /* Modal full-screen on mobile */
  .modal {
    width: 100%; max-width: 100%;
    height: 100%;
    max-height: 100%;
    border-radius: 0;
    padding: 20px;
    margin: 0;
  }
  .modal-overlay.active .modal { transform: translateY(0) scale(1); }

  /* Search full width */
  .search-input { flex: 1; min-width: 0; }

  /* Tabs scrollable */
  .tabs-bar {
    overflow-x: auto; -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .tabs-bar::-webkit-scrollbar { display: none; }

  /* Form select full width */
  .page-header .form-select { flex-shrink: 0; }

  /* Login page adjustments */
  .login-card { padding: 32px 24px; }
  .login-brand h1 { font-size: 22px; }
}

/* 2-column grid for tablets */
@media (max-width: 600px) {
  .grid-3, .grid-4, .grid-5 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 480px) {
  .grid-3, .grid-4, .grid-5 { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .stat-card { padding: 14px; }
  .stat-value { font-size: 20px; }
  .stat-label { font-size: 11px; }

  .btn-sm { padding: 7px 10px; font-size: 11.5px; }
  .page-header > div:last-child .btn-sm { white-space: nowrap; }

  .login-wrapper { padding: 0 16px; }
  .login-card { padding: 28px 20px; border-radius: var(--radius-lg); }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
  .work-card { transition: border-color var(--duration) var(--ease); }
  .work-card::before { display: none; }
  .work-card:hover { box-shadow: none; }
  .work-card:hover .work-thumb img { transform: none; }
  .work-card:active { box-shadow: 0 0 0 1px var(--accent-glow); }
  .btn:active { transform: scale(0.95); }
  .nav-link:active { background: var(--border-1); }
  .stat-card:hover { transform: none; }

  /* Larger tap targets on touch */
  .btn-sm { min-height: 36px; }
  .nav-link { min-height: 40px; }
  .data-table td { min-height: 32px; }
}

/* Safe area for notched phones */
@supports (padding-top: env(safe-area-inset-top)) {
  .mobile-header {
    padding-top: env(safe-area-inset-top);
    height: calc(56px + env(safe-area-inset-top));
  }
  .sidebar { padding-top: env(safe-area-inset-top); }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Print styles */
@media print {
  .sidebar, .mobile-header, .sidebar-overlay, .bg-grid { display: none !important; }
  .main-content { margin-left: 0 !important; }
  body { background: #fff; color: #000; }
  .data-table thead { display: table-header-group !important; }
  .data-table tbody tr { display: table-row !important; background: none; border: 1px solid #ddd; }
  .data-table td { display: table-cell !important; }
  .data-table td::before { display: none !important; }
}

/* Student folder card */
.student-folder {
  display: flex; align-items: center; gap: 16px;
  padding: 20px; cursor: pointer;
  background: var(--card);
  border: 1px solid var(--border-1);
  border-radius: var(--radius-md);
  transition: all var(--duration) var(--ease);
  animation: fadeInUp 0.4s var(--ease) both;
}
.student-folder:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 24px rgba(0,0,0,0.15);
  transform: translateY(-2px);
}
.student-folder:active { transform: scale(0.98); }
.student-folder-avatar {
  width: 48px; height: 48px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 700; color: #fff; flex-shrink: 0;
}
.student-folder-info { flex: 1; min-width: 0; }
.student-folder-name {
  font-size: 15px; font-weight: 600; color: var(--text-1);
}
.student-folder-meta {
  font-size: 12px; color: var(--text-4); margin-top: 4px;
  display: flex; gap: 12px; flex-wrap: wrap;
}
.student-folder-count {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 4px 10px; border-radius: 20px; font-size: 12px; font-weight: 600;
  background: var(--accent-glow); color: var(--accent);
}
.student-folder-arrow {
  color: var(--text-4); flex-shrink: 0;
  transition: transform var(--duration) var(--ease);
}
.student-folder:hover .student-folder-arrow {
  color: var(--accent); transform: translateX(3px);
}

/* Empty state for student works */
.student-works-empty {
  text-align: center; padding: 60px 20px;
  color: var(--text-4);
}
.student-works-empty .empty-icon { font-size: 48px; margin-bottom: 12px; opacity: 0.4; }
.student-works-empty .empty-title { font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.student-works-empty .empty-desc { font-size: 13px; }

/* Class card */
.class-card {
  padding: 20px; cursor: pointer;
  background: var(--card);
  border: 1px solid var(--border-1);
  border-radius: var(--radius-md);
  transition: all var(--duration) var(--ease);
  animation: fadeInUp 0.4s var(--ease) both;
}
.class-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 24px rgba(0,0,0,0.15);
  transform: translateY(-2px);
}
.class-card:active { transform: scale(0.98); }

/* Dashboard responsive */
@media (max-width: 900px) {
  .dashboard-row-2, .dashboard-row-3, .dashboard-row-4 { grid-template-columns: 1fr !important; }
}

/* ===== Dashboard 新增样式 ===== */

/* 卡片标题 */
.dash-card-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 16px;
}
.dash-card-title {
  font-size: 14px; font-weight: 600; color: var(--text-1);
}

/* 空状态 */
.dash-empty {
  color: var(--text-4); font-size: 13px;
  padding: 24px 0; text-align: center;
}
.dash-list:empty::after {
  content: '暂无数据'; display: block;
  color: var(--text-4); font-size: 13px;
  padding: 24px 0; text-align: center;
}

/* 列表项通用 */
.dash-list-item {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border-1);
  transition: background var(--duration) var(--ease);
}
.dash-list-item:last-child { border-bottom: none; }
.dash-list-item:hover { background: var(--glass-hover); margin: 0 -8px; padding: 8px; border-radius: var(--radius-xs); }

/* 头像 */
.dash-avatar {
  width: 32px; height: 32px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 700; color: #fff; flex-shrink: 0;
}

/* 列表文字 */
.dash-list-info { flex: 1; min-width: 0; }
.dash-list-name {
  font-size: 13px; font-weight: 500; color: var(--text-1);
  display: flex; align-items: center; gap: 6px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.dash-list-sub { font-size: 11px; color: var(--text-4); margin-top: 1px; }
.dash-list-time { font-size: 11px; color: var(--text-4); white-space: nowrap; }

/* 类型小标签 */
.dash-type-tag {
  font-size: 10px; font-weight: 700; padding: 1px 5px; border-radius: 4px;
  flex-shrink: 0; letter-spacing: 0.5px;
}

/* 课时人数角标 */
.dash-hours-badge {
  width: 36px; height: 28px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 11px; font-weight: 700; flex-shrink: 0;
}

/* 课时趋势图 */
.trend-chart { overflow: hidden; }
.trend-bars {
  display: flex; align-items: flex-end; gap: 4px;
  height: 120px; padding-top: 20px;
}
.trend-col {
  flex: 1; display: flex; flex-direction: column;
  align-items: center; height: 100%; position: relative;
}
.trend-val {
  font-size: 10px; font-weight: 700; color: var(--text-3);
  margin-bottom: 4px; opacity: 0;
  transition: opacity 0.2s;
}
.trend-col:hover .trend-val,
.trend-today .trend-val { opacity: 1; }
.trend-bar-wrap {
  flex: 1; width: 100%; display: flex;
  align-items: flex-end; justify-content: center;
}
.trend-bar {
  width: 60%; max-width: 28px; min-width: 8px;
  border-radius: 4px 4px 0 0;
  background: linear-gradient(180deg, var(--accent), var(--accent-dark));
  transition: height 0.6s var(--ease), opacity 0.2s;
  opacity: 0.7;
  position: relative;
}
.trend-col:hover .trend-bar,
.trend-today .trend-bar { opacity: 1; }
.trend-today .trend-bar {
  background: linear-gradient(180deg, var(--cyan), #0891b2);
}
.trend-bar-weekend {
  background: linear-gradient(180deg, var(--amber), #d97706) !important;
  opacity: 0.5;
}
.trend-col:hover .trend-bar-weekend,
.trend-today .trend-bar-weekend { opacity: 1; }
.trend-day {
  font-size: 10px; color: var(--text-4); margin-top: 6px;
  font-weight: 500;
}
.trend-week {
  font-size: 9px; color: var(--text-4); margin-top: 1px;
}
.trend-weekend { color: var(--amber); opacity: 0.6; }
.trend-today .trend-day { color: var(--cyan); font-weight: 700; }
.trend-today .trend-week { color: var(--cyan); }

/* 班级分布 */
.class-dist-row {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 10px;
}
.class-dist-row:last-child { margin-bottom: 0; }
.class-dist-info {
  width: 80px; flex-shrink: 0;
  display: flex; align-items: center; gap: 4px;
}
.class-dist-name {
  font-size: 12px; color: var(--text-2);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.class-dist-tag {
  font-size: 9px; font-weight: 700; padding: 1px 4px;
  border-radius: 3px; flex-shrink: 0;
}
.class-dist-bar-wrap {
  flex: 1; height: 6px; background: var(--bg-1);
  border-radius: 3px; overflow: hidden;
}
.class-dist-bar {
  height: 100%; border-radius: 3px;
  transition: width 0.6s var(--ease);
}
.class-dist-count {
  width: 28px; text-align: right; flex-shrink: 0;
  font-size: 13px; font-weight: 600; color: var(--text-1);
}

/* 趋势图响应式 */
@media (max-width: 600px) {
  .trend-bars { height: 80px; gap: 2px; }
  .trend-bar { width: 80%; }
  .trend-day { font-size: 9px; }
  .trend-week { display: none; }
  .class-dist-info { width: 64px; }
  .class-dist-name { font-size: 11px; }
  .dashboard-row-3, .dashboard-row-4 { grid-template-columns: 1fr !important; gap: 10px !important; }
  .quick-actions-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .quick-action-btn { padding: 12px 6px; }
}

/* 学生状态分布 */
.status-chart-bars { display: flex; flex-direction: column; gap: 14px; }
.status-dot {
  width: 8px; height: 8px; border-radius: 50%;
  display: inline-block; flex-shrink: 0;
}
.status-chart-item:last-child { margin-bottom: 0; }

/* 快速操作 */
.quick-actions-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.quick-action-btn {
  display: flex; flex-direction: column; align-items: center;
  gap: 8px; padding: 16px 8px; border-radius: var(--radius-sm);
  background: var(--bg-1); border: 1px solid var(--border-1);
  cursor: pointer; transition: all var(--duration) var(--ease);
}
.quick-action-btn:hover {
  background: var(--glass-hover); border-color: var(--qa-color);
  transform: translateY(-2px); box-shadow: var(--shadow);
}
.quick-action-icon { opacity: 0.85; transition: opacity 0.2s; }
.quick-action-btn:hover .quick-action-icon { opacity: 1; }
.quick-action-label {
  font-size: 12px; font-weight: 500; color: var(--text-2);
  white-space: nowrap;
}
@media (max-width: 600px) {
  .quick-actions-grid { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .quick-action-btn { padding: 12px 6px; }
}

/* ===== 视图切换按钮 ===== */
.view-toggle {
  width: 32px; height: 32px; border-radius: var(--radius-xs);
  background: transparent; border: 1px solid var(--border-1);
  color: var(--text-4); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--duration) var(--ease);
}
.view-toggle:hover { background: var(--glass-hover); color: var(--text-2); }
.view-toggle.active {
  background: var(--accent-glow); border-color: var(--accent);
  color: var(--accent-light);
}

/* ===== 课件列表视图 ===== */
.material-list-view {
  display: flex; flex-direction: column; gap: 0;
}
.material-list-row {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 16px; border-radius: var(--radius-xs);
  border-bottom: 1px solid var(--border-1);
  transition: background var(--duration) var(--ease);
}
.material-list-row:last-child { border-bottom: none; }
.material-list-row:hover { background: var(--glass-hover); }
.material-list-row.material-list-hidden { opacity: 0.5; }
.material-list-type {
  font-size: 10px; font-weight: 700; padding: 2px 6px;
  border-radius: 4px; flex-shrink: 0; width: 28px;
  text-align: center; letter-spacing: 0.5px;
}
.material-list-name {
  flex: 1; min-width: 0; font-size: 13px; font-weight: 500;
  color: var(--text-1); cursor: pointer;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.material-list-name:hover { color: var(--accent-light); }
.material-list-class {
  width: 120px; flex-shrink: 0;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.material-list-date {
  width: 80px; flex-shrink: 0;
  font-size: 11px; color: var(--text-4); text-align: right;
}
.material-list-actions {
  display: flex; gap: 4px; flex-shrink: 0;
  opacity: 0; transition: opacity var(--duration) var(--ease);
}
.material-list-row:hover .material-list-actions { opacity: 1; }

@media (max-width: 900px) {
  .material-list-row { gap: 8px; padding: 8px 10px; }
  .material-list-class { display: none; }
  .material-list-date { width: 60px; font-size: 10px; }
  .material-list-actions { opacity: 1; }
}
@media (max-width: 600px) {
  .material-list-date { display: none; }
  .material-list-actions { opacity: 1; flex-wrap: wrap; }
}